Some historians doubt Niall's existence, comparing his legend to that of King Arthur.

But scientists at Trinity College Dublin in Ireland say a distinctive genetic signature on the male Y chromosome, which is passed down from father to son, leads to Niall or some similar figure.

Niall had 12 sons, according to folklore, and took nine key hostages, including Saint Patrick, as way to subdue opponents and consolidate power.

Writing this month in the American Journal of Human Genetics, researchers said Niall "resided at the cusp of mythology and history, but our results do seem to confirm the existence of a single early medieval progenitor to the most powerful and enduring Irish dynasty."

Geographic Hotspot

The study was based on the DNA samples of 800 males across Ireland.

"We used a genetic fingerprint in the Y chromosome that was sufficiently detailed that you wouldn't expect very many men to have the same one," said Dan Bradley, a genetics professor at Trinity College Dublin.

In nothwest Ireland (map), one in five men bore the same distinctive genetic marker, the team found.

"That part of Ireland was influenced by a certain dynasty called Uí Néill [descendants of Niall]a group of lineages that held sway to a greater or lesser degree for almost a thousand years," Bradley said.

"The area of this Y chromosome coincides geographically with the greatest influence of these groups," he added.